diff options
| -rw-r--r-- | drivers/kvm/x86.c | 26 |
1 files changed, 26 insertions, 0 deletions
diff --git a/drivers/kvm/x86.c b/drivers/kvm/x86.c index 9db4e3242b6..3b79684a3c0 100644 --- a/drivers/kvm/x86.c +++ b/drivers/kvm/x86.c @@ -25,6 +25,7 @@ #include <linux/vmalloc.h> #include <linux/module.h> #include <linux/mman.h> +#include <linux/highmem.h> #include <asm/uaccess.h> #include <asm/msr.h> @@ -1674,6 +1675,31 @@ static int emulator_cmpxchg_emulated(unsigned long addr, reported = 1; printk(KERN_WARNING "kvm: emulating exchange as write\n"); } +#ifndef CONFIG_X86_64 + /* guests cmpxchg8b have to be emulated atomically */ + if (bytes == 8) { + gpa_t gpa = vcpu->mmu.gva_to_gpa(vcpu, addr); + struct page *page; + char *addr; + u64 val; + + if (gpa == UNMAPPED_GVA || + (gpa & PAGE_MASK) == APIC_DEFAULT_PHYS_BASE) + goto emul_write; + + if (((gpa + bytes - 1) & PAGE_MASK) != (gpa & PAGE_MASK)) + goto emul_write; + + val = *(u64 *)new; + page = gfn_to_page(vcpu->kvm, gpa >> PAGE_SHIFT); + addr = kmap_atomic(page, KM_USER0); + set_64bit((u64 *)(addr + offset_in_page(gpa)), val); + kunmap_atomic(addr, KM_USER0); + kvm_release_page_dirty(page); + } +emul_write: +#endif + return emulator_write_emulated(addr, new, bytes, vcpu); } |